The Shimmering Ruins, Nevarl and Laurent are part of Water Country Topple.The Shimmering Ruins are filled with Water despite it being the location of the Mana Stone of Light and Nevarl was once a Jungle according to Flamekin so it obviously had it's jungle burned into the Burning Sands of Nevarl by the Mana Stone of Fire.
Molebear Highlands, Valsena and Gemstone Valley Dorian are all part of Ishe.Watts lived in the country those three areas are located in and he is the ruler of Ishe...
Altena became the Empire.Since the Empire is on the exact same continent as Altena it is obvious that Altena is the original form of the Empire.
Wendel was taken over by priests of Lorimar until after Trials of Mana.Wendel was mentioned in the Empire's backstory shown by the Mandala's crystal orbs as being the capital of Lorimar which indicates that Stroud's Kingdom moved it's capital to one of it's conquered countries following Lorimar's transformation into the Dark Castle seen in SD3. Considering that Niccolo was the orriginal ruler of Wendel the Beastmen may be the true people of Wendel. At some point the Lorimarian Priests of Wendel were driven out(by either the Empire or the Beastmen who originally ruled Wendel in the first place) and had to flee back to Lorimar and make a deal with Emperor Vandole for immortality freezing Lorimar into the Ice Country again.interesting how the desert in the Fire Country is called Arid Sands while the desert in the Water Country is called Burning Sands).
The Thieves's Guild of Nevarl was driven out by Sage Luka and the Elves of Doirre to establish Pandora.The ruins east of Pandora are inside a desert so it's obvious that those are the ruins of the Sand Fortress of Nevarl. Flamekin suceeded in turning the desert back into a jungle only for the elves to come back from Doirre and reclaim the lands they once ruled(Luka is an Elf and was the original ruler of Topple so obviously she would want to reclaim her old kingdom) while establishing the vassal Kingdom of Pandora(Primm is a noble and is clearly an elf judging from her ears).
Vandole is the Echoes of Mavolia.He did say that he'll exist as long as Mana did you know...
- Confimed by the Dummied Out diary in Secret of Mana which claims that the Emperor is actually a dark power imitating human form...
The Dragon Emperor was possessed by Vandole/Echoes.The Dragon Emperor appeared in Legend of Mana as the ruler(though not creator since that is Anise/Medusa) of Mavolia under the name Tiamat(in the japanese version which is the most canon) and later reappears as one of Vandole's slaves in Sword of Mana so obviously the Emperor possessed him.
Dragon Emperor Tiamat/Drakonis, Malyris/Malyrith/Hexas/Fanha/Kary, Kraken and the Lich/Dark Lich are the Four Fiends of Final Fantasy I.World of Mana franchise is a spinoff of Final Fantasy so it makes sense though why Chaos's Fiends would appear in the World of Mana is unknown.
Sir Thanatos is actually Lich possessed by Thanatos servants of the Echoes.The name makes it obvious.
Sir Dyluck is the unconcious avatar of Prince Durac(looks like Dyluck and has the same name in Japan) from Sword of Mana.Considering Vandole's deal froze Durac and all of Lorimar it's obvious that it was planned by Sir Thanatos as a means to obtain a body thus explaining the "born in Darkness and raised in the Light of Mana" line refering to Dyluck's compatability since what's less likely to fight off another soul than a souless avatar of a frozen prince? Unfortunatly for Thanatos(and Dyluck) the soul of Durac that unconciously controlled the avatar known as Dyluck was actually inhabting Dyluck's body all along(his real body wasn't likely to move so obviously the soul would inhabit the moving body it controlled rather than the body it didn't) and caused a rejection blowing up Dyluck in the process leaving Thanatos without a body and returning Durac to his own still frozen body.
Thanatos Lich/Dark Lich possessed Belgar after or during the ending of Heroes of Mana.Why else would Belgar hate humanity unless he was possessed by another entity and considering how the Dark Lich possesses bodies...
The Isabella from Sword of Mana is the same one from Trials of Mana after recieving Laser-Guided Amnesia.Mavolia's rules according to Sword of Mana states that Mavolians that fall in love with humans will get their memories erased when caught by the ruler(The Dragon Emperor)... Obviously that happened(most likely for fighting against Dragon Emperor in order to revive the Dark Lord) the moment Bigieu returned to Mavolia when planning to commit suicide and since her diary used her fake persona(to keep Nevarl soldiers from finding out she was a Mavole) she started going by that name: Isabella. This clearly implies that the Archdemon boss fight is non-canon.
In relation to the above: Duran and Angela's final boss fight against the Dragon Emperor is canon.Since the Dragon Emperor is likely the only one(aside from Anise/Medusa) to have the power to erase memories unlike the Lich. Add that to the fact that Duran's sword Excalibur turned into the third Mana Sword(first was Stroud's and the second was absorbed by the final boss) which would logically only happen if Duran was the main character and you get the Dragon Emperor is the canon Final Boss.
The Dragon Emperor ressurected Stroud and applied Laser-Guided Amnesia on him making him the Dark Lord of Sword Of Mana.Considering his power to erase memories, his power in general(has more health than Archdemon) and his possession of the Mana Sword the Dragon Emperor may have ressurected Stroud even without his remains or his Thanatos based power and erased his memories then introduced him to his older brother Devius and the illness of his mother Anise/Medusa which would eventually lead him to commit the actions he commited in Sword of Mana. There would be no need for the Dragon Emperor to inform the amnesiac Stroud about his crimes against his younger brother Keldric since he does not want a rival to his power.
Durac is Vandole's true descendant.Durac has the same face as Vandole's Julius identity and his presumed avatar Dyluk has associations with darkness according to Thanatos so I theorize that Durac is Vandole's true descendant(not suprising considering Durac's Kingdom of Lorimar's constant Deals with the Devil).
Mathilda(Legend Of Mana) is not an idiot, just suicidal.Mathilda felt trapped in her priestess duties and Irwin stealing her elemental powers, which forced her to age rapidly didn't help. She encourages Irwin to give into his destructive urges in the hopes he will kill her, ending her suffering, and possibly kill those who she views as responsible for forcing her into this position. When Irwin and Mathilda meet in the Netherworld, Irwin just walks a way from her without explanation. Perhaps he felt used by her.